1. Field of the Invention
The present invention relates to a spray nozzle assembly which can be useful for remote installation of sealant material in a mine entry to close the opening during heating events and other dangerous conditions that limit or prevent safe access to the mine.
2. Description of Related Art
For as long as minerals such as coal have been extracted from underground deposits, miners and underground workers have been confronted with hazards and dangerous events, often resulting in cessation of mining operations until underground conditions can be rendered safe. Such situations include, for example, accumulation of toxic and explosive gases, underground fires or heating events, flooding, and combinations thereof. The interruptions in operation result in lost revenue from lack of product sales, and ultimate loss of workforce and customers when the dangerous conditions can only be remedied over extended periods of time.
Many attempts have been made to render hazardous conditions safe for continued underground operations. For example, the mine can be sealed for long periods of time to allow flood waters naturally recede or a fire to burn itself out from lack of combustible materials and/or oxygen and to permit the surrounding areas to cool and dissipate toxic and/or explosive gases.
Alternatively, the unsafe areas of the mine can be isolated from other working areas by installing strong, generally air-tight seals between the unsafe areas and working areas. This approach is also used to seal off smaller segments of the underground workings to contain toxic gases or cut-off air supply so that a fire can extinguish itself in a shorter period of time.
Such sealing efforts can also enable exchange of the atmosphere near the hazard with inert gas to extinguish a fire or to displace toxic or explosive gas, as well as to introduce a breathable atmosphere as needed. In gaseous underground workings such as coal mines, workers can experience significant increases in amounts of methane gases, as well as in underground heating event scenarios where black and white damp can displace breathable air. Black damp generally refers to carbon dioxide, but is more specifically used to refer to mixtures of carbon dioxide and nitrogen, as well as to oxygen depleted atmospheres. White damp generally refers to carbon monoxide that can predominate afterdamp atmospheres resulting from fires, blasting, explosions of gas, coal-dust, or other underground contaminants.
In the past, such sealing efforts have been ineffective as it is difficult to install a seal near the fire or source of unsafe gas(es). To be effective, the mine seal should extend across the ribs or sidewalls, and from floor to roof of an entry, and have a thickness and depth sufficient to withstand explosion or the weight of dammed-up flood water. Such seals are typically used to isolate the fire area and to limit the inflow of oxygen. Once an area is sealed, the fire can be more readily controlled or suppressed by flooding the area behind the seals with water, gas-enhanced foam, inert gas, silt or other material. Such seals have been made from wood, steel, concrete, and grout materials when the seal can be constructed from underground locations near the hazard or problem area.
However, most underground mines cannot dissipate heat or gas except through nearby passageways. Such passageways can extend for miles before reaching vents, which are usually the mine adits or entries. Therefore, it can be difficult to install a seal in underground locations near the problem area. Attempts have been made to remotely install a seal close to a problem area from a location that is a safe distance from the dangerous problem area (“PA”), such as from the surface (“S”). As shown in FIG. 1, a drill rig (“DR”) can be positioned to drill a down shaft, hole, or bore (“DS”) near the problem area.
However, such efforts have been less than satisfactory because it is difficult to install a seal close enough to the problem area or to effectively seal the passageway or entry. In many remote seal installations, it has been difficult to adequately close gaps between the top of the seal and the roof of the problem area PA because the body of the seal base can shrink and settle after installation, creating gaps therebetween.
Despite these problems, mine operators and government legislators in the United States and elsewhere seek to reduce the hazards confronting underground workers by focusing on improving the state of the art of remote seal construction and installation. Therefore, there is a need in the art for apparatus and systems that are capable of use for remote sealing of underground passageways or entries to close the opening during heating events and other dangerous conditions that limit or prevent safe access to the underground works.